Restoration of Elbow Flexion in Patients With Complete Traumatic and Obstetric Brachial Plexus Injury After Functional Free Gracilis Muscle Transfer: Our Experience and Management

Background: Functional free gracilis muscle transfer is an operative procedure for elbow reconstruction in patients with complete brachial plexus nerve and avulsion injuries and in delayed or prolonged nerve denervation, as well as in patients with inadequate upper extremity function after primary nerve reconstruction. Methods: We retrospectively reviewed our patient records and identified 24 patients with complete brachial plexus nerve injury (13 obstetric, 11 males and 2 females; 11 traumatic, 9 males and 2 females) whose affected arm and shoulder were totally paralyzed and their voluntary elbow flexion or the biceps function was poor preoperatively (mean M0-1/5 in MRC grade). These patients had undergone the functional free gracilis muscle transfer procedure at our clinic since 2005. Results: Ninety-two percent of all patients showed recovery and improvement. Successful free gracilis muscle transfer is defined as antigravity biceps muscle strength of M3-4/5 and higher, which was observed in 16 (8 obstetric and 8 traumatic) of our 24 patients (67%) in this study at least 1 year after functional free gracilis muscle transfer. This is statistically significant (P < .000001) in comparison with their mean preoperative score (M0-1/5). There was no improvement in motor level of the biceps muscle (M0/5) in 2 patients (1 from each group). The donor site of these 24 patients showed no deficit in motor and sensory functions. Conclusions: Taken together, a significant number (92%) of patients in both obstetric and traumatic brachial plexus injury groups had recovery and improvement and most of these patients (64%) achieved antigravity and elbow flexion at least 1 year after free gracilis muscle transfer at our clinic.

Background: Functional free gracilis muscle transfer is an operative procedure for elbow reconstruction in patients with complete brachial plexus nerve and avulsion injuries and in delayed or prolonged nerve denervation, as well as in patients with inadequate upper extremity function after primary nerve reconstruction. Methods: We retrospectively reviewed our patient records and identified 24 patients with complete brachial plexus nerve injury (13 obstetric, 11 males and 2 females; 11 traumatic, 9 males and 2 females) whose affected arm and shoulder were totally paralyzed and their voluntary elbow flexion or the biceps function was poor preoperatively (mean M0-1/5 in MRC grade). These patients had undergone the functional free gracilis muscle transfer procedure at our clinic since 2005. Results: Ninety-two percent of all patients showed recovery and improvement. Successful free gracilis muscle transfer is defined as antigravity biceps muscle strength of M3-4/5 and higher, which was observed in 16 (8 obstetric and 8 traumatic) of our 24 patients (67%) in this study at least 1 year after functional free gracilis muscle transfer. This is statistically significant (P < .000001) in comparison with their mean preoperative score (M0-1/5). There was no improvement in motor level of the biceps muscle (M0/5) in 2 patients (1 from each group). The donor site of these 24 patients showed no deficit in motor and sensory functions. Conclusions: Taken together, a significant number (92%) of patients in both obstetric and traumatic brachial plexus injury groups had recovery and improvement and most of these patients (64%) achieved antigravity and elbow flexion at least 1 year after free gracilis muscle transfer at our clinic. ePlasty VOLUME 17 Functional free gracilis muscle transfer (FFGMT) is an operative procedure for restoration of elbow flexion in patients with complete brachial plexus nerve injuries and in delayed or prolonged nerve denervation, as well as in patients with inadequate upper extremity function after primary nerve reconstruction. [1][2][3][4][5][6][7][8][9] In a total or complete brachial plexus injury (CBPI), the entire plexus is injured and that is more devastating. Twenty percent of patients with obstetric brachial plexus injury (OBPI) are CBPI, which severely compromises the patient's overall upper extremity functions and growth. 10,11 Traumatic brachial plexus injury (TBPI) is also a severe and devastating condition observed in up to 4.2% of multitrauma victims. 12 The management of complete or avulsion (preganglionic lesion) injuries is challenging using mainly nerve transfer or graft procedures in both OBPI and TBPI patients due to its complexity of the injury.
Functional free muscle transfer (FFMT) with nerve transfer has been commonly adopted for gaining elbow flexion in these patients. [1][2][3][4][5][6][7][8][9] Limited donor nerve for nerve transfer and long distances to the target muscle are the main obstacles in these patients. Therefore, the FFMT is the only option to improve their limb function. The functioning gracilis muscle is used as the functional deficit after gracilis harvest is negligible. 1 Here, we report the outcomes, in particular, the biceps function/elbow flexion after FFGMT in 24 patients with complete brachial plexus nerve injury (13 obstetric and 11 traumatic) who lost their biceps strength and function.

Inclusion criteria
Both OBPI and TBPI patients, who had no visible biceps function and no elbow flexion, were included.
We retrospectively reviewed our patient records with brachial plexus nerve injury and identified 24 severely paralyzed patients (13 obstetric, 11 males and 2 females; 11 traumatic, 9 males and 2 females) who had no elbow flexion and had undergone FFGMT at our clinic since 2005. The median (18), radial (5), and ulnar (1) nerves reinnervated the transferred gracilis muscle in our patients with brachial plexus injury (BPI) in the present study.
Results were assessed by the MRC grading system. Mean age at the time of surgery was 10 years (range, 5.4-14.2 years) in obstetric patients and 27 years (range, 8-50 years) in traumatic patients. Voluntary elbow flexion or the biceps function was very poor before FFGMT (mean = M0-1/5 in MRC grade) in most of our patients in this study.
Written informed consent was obtained from all patients for publication and accompanying images. A copy of the written consent is available for review on request. This was a retrospective study of patient charts, which exempted it from the need for institutional review board approval in the United States. Patients were treated ethically in compliance with the Helsinki declaration. Documented informed consent was obtained for all patients.

RESULTS
Taken together, a significant number of patients (92%) in both OBPI and TBPI groups had recovery and improvement (Table 1). Successful FFGMT is defined as antigravity biceps muscle strength of M3-4/5 and higher, which was observed in 16 (8 obstetric and 8 traumatic) of our 24 patients (67%) in this study at least 1 year after FFGMT (Table 1 and Figure 1). This is statistically highly significant (P < .000001) in comparison with their mean preoperative score (M0-1/5). There were some recovery and improvement (M1-2/5) in 6 patients (4 from OBPI and 2 from TBPI), but they did not achieve antigravity. There was no improvement in motor level of the biceps muscle (M0/5) in 2 patients (1 from each group).
The donor gracilis muscle of these 24 patients showed no deficit in motor and sensory functions.

DISCUSSION
Several authors have described a number of functional muscle transfer surgeries involving latissimus dorsi (LD) [13][14][15][16][17][18] trapezius transfer, 18-20 pectoralis major, 21,22 rectus femoris muscle, 23 and gracilis [1][2][3][4][5][6][7][8][9] to restore elbow flexion and hand and shoulder functions. These authors have reported a range of outcomes in patients with complete or preganglionic severe BPI. For example, Kawamura et al 24 reported that 50% of patients did not achieve sufficient elbow flexion after initial LD transfer in a series of 10 patients. The muscle was deemed too long and had to shorten at the distal end of the transfer to achieve better outcomes in this series. 24 LD transfer in BPI patients is mainly used to restore external rotation at the shoulder. 25 Maldonado et al 26 showed 67.7% success in their TBPI patients, achieving elbow flexion after the FFGMT procedure. Gardiner and Nanchahal 27 found 91% to 99% success using FFGMT. Yet, other investigators 28 reported an overall failure rate of 15.4%.
Hattori et al 29 studied comparison between spinal accessory (SAN) and intercostal nerve (ICN) reinnervation and showed that the contraction rate was significantly higher among the transferred muscles reinnervated by the SAN than those by the ICN. We have not found such significant differences in the outcome based on the nerves used in FFGMT in our study patients. We have used a part of the transplanted vascularized median or radial or ulnar nerve as a motor source of a free muscle graft. Chung et al 30 achieved 78% success using the gracilis muscle in 23 of their patients following transfer of 3 ICNs. These authors also found a greater increase in elbow flexion when ICNs were transferred to innervate the gracilis flap than ulnar fascicles.

COMPLICATIONS OF FFGMT
Hattori et al 31 detected obturator nerve injury associated with femur fracture fixation during gracilis muscle harvesting for FFGMT. The most common late complication reported was fracture of the clavicle (5.4%). 28 One of our patients has lost some strength due to tendon lengthening, although gained antigravity function (biceps M3 and above) after FFGMT. This patient was recommended for FFGMT tightening with longer (6-month) immobilization.

CONCLUSIONS
Taken together, a significant number (92%) of patients in both OBPI and TBPI groups had recovery and improvement and most of these patients achieved antigravity and elbow flexion at least 1 year after free gracilis muscle transfer at our clinic.

AUTHOR CONTRIBUTIONS
R.K.N. conceived of the study, R.K.N. and S.G.B. performed all the surgeries and revised the manuscript. C.S. participated in the design of the study, gathered data, performed the statistical analysis, and drafted the manuscript. All authors read and approved the final manuscript.